NO156248B - PROCEDURE FOR THE PREPARATION OF POLYUREAPOLYURETHAN PRODUCTS BY REACTION SPRAY CASTING. - Google Patents

Abstract

The use of certain prepolymers of 4,4'-methyienebis-(phenyl isocyanate), in place of the latter diisocyanate itself in the preparation of polyurethane-polyureas using aromatic diamine extenders, has a number of advantages par- ticuiariy when the compositions are prepared by reaction injection molding techniques using two streams of reactants. The principal advantages are (i) a useful increase in gel time and (ii) a ratio of amounts of the two reactant streams which more nearly approaches 1:1.This latter factor not only improves the efficiency of mixing of the components in the mixing head but, together with the longer gel time, significantly increases the output of mixed reactants per unit of time. The prepolymers of 4,4'- methyienebis(phenyi isocyanate) employed to achieve the above results are those derived from polyoxy-ethylene polyoxypropylene polyether diols and triols (MW = 1000-10.000), polytetramethylene glycols (MW = 600-5.000) and polyester diols and triols (MW = 500-8.000).

Description

Pest control agent.

This invention relates to pest control agents which are particularly suitable for the control of Arthropoda and Nematoda.

The agents according to the invention charac-

can be seen in that as active ingredients they contain compounds that can be represented by the general formulas where their numbering system is also indicated:

where R 1 , R 2 , R 3 and R 4 are each hydrogen atoms, alkyl or alkenyl groups of one to three carbon atoms; R 1 and R 2 are each hydrogen atoms, alkyl, alkenyl and alkynyl groups having one to three carbon atoms,

and X is oxygen or sulfur; X means one or more substituents selected from hydrogen atoms, halogen atoms and lower alkyl groups, and n is an integer from 1 to 3.

Compounds of the class defined above exhibit excellent activity against

pests, including effective activity against Nematoda and against Arthropoda such as Coleoptera (beetles), Hemiptera (true insects), Homoptera (aphids), Acarina (mites), Diptera (flies and wasps), Blattaria (cockroaches), and Lepidoptera ( moths and summer birds).

Certain connection that is preferred

in the agents according to the invention, include compounds of the general formulas:

where R] and R 2 are each hydrogen or methyl, R 3 is hydrogen or an aliphatic group of one to three carbon atoms, and Y t and Y 2 are each hydrogen, halogen or lower alkyl.

The production and pest control activity of typical compounds used in the agents according to the invention are illustrated in the following examples. All parts are by weight unless otherwise noted, and all temperatures are degrees Celsius.

Example 1.

Production and pest control properties of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate.

This compound was prepared by a method in which 2-methallyloxyphenol was simultaneously cyclized and rearranged to form a 7-benzofuranol, followed by esterification to form the carbamate. The starting material 2-methallyloxyphenol was prepared as follows: To a stirred mixture of 322 parts of catechol in 300 parts of dry acetone, 401 parts of potassium carbonate and 481 parts of potassium iodide were slowly added, under a nitrogen atmosphere. The mass was heated to boiling, and 262 parts of methalyl chloride was slowly added. The mixture was refluxed for 30 hours, allowed to cool and stand for 18 hours, filtered, and the filtrate was concentrated under reduced pressure. The remaining oil was extracted with chloroform, and the chloroform solution was washed with water, dried and concentrated. The remaining oil was distilled to give 213 parts of 2-methallyloxyphenol, b.p. 78.5— 83.0°/0.55 mm Hg, n ™ 1.5300.

2,3-dihydro-2,2-dimethyl-7-benzofuranol was prepared as follows: A round-bottomed flask containing 131 parts of 2-methallyloxyphenol was slowly heated under

stirring. At 200° an exothermic reaction took place, and the temperature of the mixture in the flask rose rapidly to 275°. The temperature was maintained at 275° by means of external cooling. The thick syrup was distilled under reduced pressure to give colorless liquid 2,3-dihydro-2,2-dimethyl-7-benzofuranol, m.p. 78—80° (0.35—0.40 mm Hg), n 2D5 1.5401.

2,3-dihydro-2,2-dimethyl-7-benzofuranol-N-methylcarbamate was prepared as follows: A cold solution of 16.4 parts of 2,3-dihydro-2,2-dimethyl-7-benzofuranol in 14 parts ether was treated with 5.8 parts of methyl isocyanate and 0.1 part of triethylamine. The mixture was stirred at room temperature and a white crystalline product precipitated. Separation of the solid gave 17.5 parts of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate, m.p. 151—152°. Recrystallization from methylcyclohexane gave an analytical sample.

Analysis: Calculated for C{ 9H.^ NO, : N 6.33. Found: N 6.57.

Insecticidal activity was measured as follows: The compound 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate was dissolved to form a 1% solution in acetone, which was then diluted with water to give a concentration of 1250 ppm of the active ingredient. Test insects and methods were as follows: The activities against Mexican bean beetles (Epilachna varivestis Mulsant) and Prodenia eridania Cramer were determined by dipping the leaves of pinto bean plants in the test solution and infesting the leaves with the test insects; the activity against two-spotted spider mite (Tetranychus telarius Linnaeus) was determined on pinto bean plants whose leaves were dipped after infection; the activity against pea aphid (Macrosiphum pisl Harris) was determined on broad bean plants whose leaves had been dipped before infection; and the activity against Oncopeltus fasciatus Dallas was determined by spraying the sample solution on glass dishes containing the insects. After the insects had been exposed to the test solutions for 72 hours, the percentage mortality was determined. The results given below and in the following examples are each the average of two or more experiments.

The procedure followed to assess the activity against houseflies was as follows: One microliter of a solution of ^ 200 mg of the test compound in 100 ml of acetone j was applied to the bodies of each of 35 to 45 three- to four-day-old houseflies (Musea j domestica). The activity against cockroaches was assessed in a similar way by using 20 adult male German cockroaches

(Blatella germanica). After 24 hours, the percentage mortality was determined by counting the dead and live insects.

Nematode control was measured as follows: A nematode-infected soil was prepared by mixing approx. 1000 larvae of the root-knot nematode (Meloidogyne incognita var. acrita) in one liter of sandy clay soil. Into this infected soil was mixed enough of the test compound, in the form of a 5 percent dust on attapulgite clay, to give a concentration of 25 ppm. This mixture was kept in a greenhouse in a moist condition for 4-7 days, and then young tomato plants were planted in the soil and allowed to grow for 4-6 weeks. After sufficient growth was achieved, the roots of the tomato plants were washed free of soil, and the degree of infection was assessed by comparison with a plant grown in nematode-infested soil that had not been given any chemical treatment. The results, as indicated in the table below and

in the following examples, represents the average of two trials.

Example 2.

Preparation and properties of 2, 3-dihydro- 2, 2- dimethyl- 4- benzofuranyl-N- methylcarbamate.

This compound was prepared by

-jelp of the following series of reactions: to a solution of 168 g of methyl beta-:esorcylate in 250 ml of methanol was added 54 g of sodium methoxide over a period

in 20 minutes. The reaction mass was cooled and 100 g of 3-chloro-2-methylpropene was added. The mixture was boiled under reflux for 2y2 hours and allowed to stand for 116 hours. The slurry was filtered to remove the precipitated sodium chloride, and the filtrate was concentrated and distilled to give a fraction with a boiling point of 120-130° (0.3 mm Hg). The distillate was cooled to 0° and filtered to separate 64.2 g of solid starting material from the 75.2 g of oil. This oil was very slowly dissolved in a cold, stirred solution of 20 g of sodium hydroxide in 500 ml of water. The slurry was stirred for an additional 30 minutes, filtered, and the solid was washed with 30 mL of water and then with 50 mL of ether to give 74 g of the sodium salt. This was added to a mixture of 50 ml of concentrated hydrochloric acid, 250 g of ice and 100 ml of ether. The aqueous layer was extracted twice with 100 mL portions of ether, and the combined ether layers were dried over magnesium sulfate and concentrated to give 47.0 g of methyl 4-((2-methylallyl)-oxy)salicylate as crude product with a melting point 35-36°. An analytical sample was recrystallized three times from pentane to melt at 36-37°. When the infrared spectrum showed the presence of hydrogen bonding, the free hydroxyl group was shown to be in the ortho position to the ester group.

Analysis: Calculated for CiTKuO4: C 64.85, H 6.35.

Found: C 64.80, H 6.53.

46 grams of the above ester was slowly heated in a nitrogen atmosphere. At 240°, an exothermic reaction took place, and the temperature rose to 290°. The oil was held at 250° for a further 20 minutes, and

then allowed to cool. The semi-solid was recrystallized from a mixture of methanol and water, and from hexane to give 9.5 g of methyl-4-hydroxy-2,3-dihydro-2,2-dimethyl-5-benzofurancarboxylate as crude product with a melting point of 89 -93°. Saponification was carried out by refluxing a mixture of 9.2 g of this ester with 50 ml of 10% sodium hydroxy solution for 2 hours. After cooling

and acidifying the mixture with 15 ml of concentrated hydrochloric acid, the crude 4-hydroxy-2,3-dihydro-2,2-dimethyl-5-benzofurancarboxylic acid was extracted with ether. The ether solution was dried over magnesium sulfate and concentrated to give 9.0 g of product. This acid (8.6 g) was decarboxylated by heating at 210-220° for half an hour. After cooling, the liquid was distilled to give 2.8 g of 2,3-dihydro-2,2-dimethyl-4-benzofuranol with a boiling point of 108-111° (0.5 mm Hg). This oil solidified and melted at 89-91°. The structure of this compound was confirmed by infrared analysis.

Analysis: Calculated for C1()H1pOp: C 73.14, H 7.31.

Found: C 72.94, H 7.56.

This phenol was esterified according to the procedure described in example 1. Reaction of 1.9 g of 2,3-dihydro-2,2-dimethyl-4-benzofuranol with 0.8 g of methyl isocyanate gave 1.9 g of 2,3-dihydro -2,2-dimethyl-4-benzofuranyl-N-methylcarbamate, which melted at 117-118° after recrystallization from carbon tetrachloride and from methylcyclohexane. Infrared analysis confirmed the structure of this product.

Analysis: Calculated for C12H]5NOg: N 6.33. Found: N 6.32.

Following the test conditions described for the compound in Example 1, 2,3-dihydro-2,2-dimethyl-4-benzofuranyl-N-methylcarbamate at 1250 ppm exhibited 100 percent mortality to Mexican bean beetle, 100 percent mortality to two-spotted mite, 100 percent mortality for Oncopeltus fascinatus, 95 percent mortality for pea aphids, and 100 percent mortality for houseflies.

Example 3.

Production and insecticidal properties of 2, 3- dihydro- 7- benzofuranyl-N-methylcarbamate.

The 7-benzofuranol intermediate was prepared from 2-hydroxy-m-anisaldehyde by the following series of reactions: To a reflux-boiling solution of 26.5 g of 2-hydroxy-m-anisaldehyde and 28.7 g of ethyl bromoacetate in 100 ml of absolute ethanol' was added dropwise to a solution prepared by dissolving 7.5 g of sodium in 200 ml of absolute ethanol. The mixture was refluxed for an additional 3½ hours and stirred overnight. A solution of 7.5 g of potassium hydroxide in 100 ml of water was added, and the ethanol was removed by distillation. The residue was cooled, acidified with 6 N hydrochloric acid and allowed to stand

overnight. The precipitate was isolated by filtration and dissolved in sodium bicarbonate solution. This solution was washed with ether and acidified to give 18.3 g of crude 7-methoxy-2-benzofurancarboxylic acid, m.p. 209-211°. A mixture of 10 g of this acid and 185 ml of chlorobenzene was stirred and heated on a steam bath while 26 g of anhydrous aluminum chloride was added

portionwise. After half an hour of heating, the solution was poured onto ice and diluted hydrochloric acid. The chlorobenzene was removed by steam distillation, and the product was extracted with methyl acetate. The organic solution was dried over magnesium sulfate and concentrated to dryness under vacuum to give 7.5 g of 7-hydroxy-2-benzofuran carboxylic acid, mp 192-197°. The solid crude product was recrystallized from water to melt at 218-220°. A mixture of 11.3 g of this recrystallized product, 76 g of refined quinoline and 1.5 g of copper powder was heated at 120-125° until evolution of carbon dioxide ceased. The cooled mixture was diluted with 250 ml of ether and filtered. The filtrate was washed with three 150 ml portions of 3 N hydrochloric acid and with a 200 ml portion of water. It was dried over magnesium sulfate and distilled. After removal of the ether and the quinoline, a yield of 3 and 7-benzofuranol with a boiling point of 72-78° (0.2 mm Hg) was obtained.

This phenol was esterified by the following process: 4 drops of triethylamine were added to a mixture of 3.1 g of 7-benzofuranol and 1.7 g of methyl isocyanate. An exothermic reaction immediately took place. The mixture was heated at 45-50° for 24 hours and poured into water. The water was extracted with ether, the ether solution was dried and concentrated to dryness under vacuum to give 3.4 g of crude 7-benzofuranyl-N-methylcarbamate, mp 137-138°. This compound was recrystallized from benzene.

Analysis: Calculated for C10H0NO3: C 62.82,

H 4.71, N 7.33

Found: C 62.62, H 4.89, N 7.58.

A mixture of 6 g of 7-benzofuranyl-N-methylcarbamate in 350 ml of anhydrous ethanol and 1.5 g of 10% palladium on charcoal was shaken in a hydrogen atmosphere of 3.3 atm.

(49 pounds). When the theoretical amount of hydrogen had been absorbed, the catalyst was removed by filtration, and the filtrate was dried over magnesium sulfate. The ethanol was removed and the remaining solid was recrystallized from methylcyclohexane

to give 4 g of pure 2,3-dihydro-7-benzofuranyl-N-methylcarbamate with a melting point of 145-147°.

Following the test method as described for the compound in Example 1, 2,3-dihydro-7-benzofuranyl-N-methylcarbamate exhibited 100% mortality to Mexican bean beetle, 100% mortality to Oncopeltus fasciatus and 100% mortality to houseflies .

Example 4.

Production and properties of 2, 3-dihydro-2-methyl-7-benzofuranyl-N-methylcarbamate.

The 2,3-dihydro-2-methyl-7-benzofuranol intermediate was prepared from catechol by the following series of reactions: By the method of Perkin and Trikojus (J. Chem. Soc, 1927, 1664), 4 moles of catechol, 4 moles of potassium carbonate and 4 moles of 3-bromopropene in 500 ml of acetone reacted, and the product was distilled to give 219 g of 2-(allyloxy)-phenol, b.p. 75—80° (0.7—1.4 mm Hg), 1.5391. This compound was recrystallized at 200-275° and distilled through a 30 cm Vig-reaux column to give 171 g of a mixture of 3- and 4-allylcatechol (b.p. 83-90° at 0.25 mm Hg) and 16 .5 g of 4-allylcatechol with a boiling point of 90-93° (0.25 mm Hg), m.p. 39-42°. This last fraction was recrystallized from methylcyclohexane to melt at 46.0-47.5° (lit. m.p. 48°). The mixed isomeric fraction was redistilled to give 72.1 g of 3-allylcatechol, bp 105-110° (1.6 mm Hg), n» 1.5613.

The 3-allylcatechol was cyclized as follows: A mixture of 35 g of 3-allylcatechol, 35 g of dimethylaniline hydrochloride and 0.1 g of hydroquinone was heated for 6.75 hours at 175-185°, cooled, and diluted with 7 ml of ether. The slurry was washed with four 35-ml portions of water, the organic phase was dried over magnesium sulfate, filtered and distilled to give 13.6 g of 2,3-dihydro-2-methyl-7-benzofuranol with a boiling point of 76-77° ( 0.7 mm Hg),^ 1.5535. The structure of this compound was confirmed by nuclear magnetic resonance studies.

The carbamate ester was formed by reacting the phenol intermediate with methyl isocyanate as follows: 2,3-dihydro-2-methyl-7-benzofuranol (13.6 g) was reacted with 5.7 g of methyl isocyanate, and the solid product was recrystallized from methylcyclohexane : to give 8.5 g of 2,3-dihydro-2-methyl-7-benzofuranyl-N-methylcarbamate with a melting point of 118.5-120.0°. Another recrystallization from carbon tetrachloride raised the melting point to 121—

122°. The structure was confirmed by nuclear magnetic resonance studies.

Analysis: Calculated for C^HjgNOg: N 6.76. Found: N 6.84.

Following the test method described for the compound in Example 1, 2,3-dihydro-2-methyl-7-benzofuranyl-N-methylcarbamate at a dilution of 1250 ppm showed 100 percent mortality to Mexican bean beetle, pea aphid, Prodenia eridania and Oncopeltus fasciatus , 97 percent mortality for two-spotted mites, and 100 percent mortality for houseflies.

Example 5.

Preparation and properties of 2,3-dihydro-2,2-dimethyl-1'-benzo-furanylcarbamate.

The 2,3-dihydro-2,2-dimethyl-7-benzofuranyl chloroformate intermediate was prepared as follows: A stirred solution of 215 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranol and 100 ml of phosgene was kept at 4-7° while 131 g of triethylamine was added dropwise. The solution was stirred for an additional hour at 5° and was then diluted with 400 ml of cold water. The benzene solution was washed with 20 per cent hydrochloric acid solution and with water until the aqueous extracts were neutral. The organic layer was dried over magnesium sulfate and concentrated under vacuum to give 239 g of crude 2,3-dihydro-2,2-dimethyl-7-benzofuranyl chloroformate, mp 88-91°.

A solution of 10.8 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl chloroformate in 75 ml of ether was slowly added to a stirred mixture of 2.8 ml of 30% ammonium hydroxide solution and 25 ml of ice water, the temperature being kept at 5°. The mixture was stirred for one hour at 5° after the addition was complete. The solid material that precipitated was separated by filtration at 5°, washed with water and dried to give 5.8 g of crude 2,3-dihydro-2,2-dimethyl-7-benzofuranyl carbamate, m.p. 153— 157°. Recrystallization from benzene gave 3.5 g of pure product with a melting point of 173.5-174.5°.

Analysis: Calculated for CnH13NO:1: N 6.76. Found: N 6.94.

Following the procedure described in Example 1, the compound 2,3-dihydro-2,2-dimethyl-7-benzofuranylcarbamate exhibited 100 percent mortality to Mexican bean beetle and 100 percent mortality to pea aphid.

Example 6.

Preparation and properties of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N,N-dimethylcarbamate.

To a cold, stirred solution of 50.0 g of 2,3-dihydro-2,2-dimethyl-7-benzoiuranol in 100 ml of ether was slowly added a solution prepared by dissolving 6.9 g of sodium in 120 ml of ethanol . The dark solution was stirred for an additional 1/2 hour and was concentrated in vacuo to give 58.8 g of crude sodium salt. To a stirred solution of 27.9 g of this sodium salt in 75 ml of chloroform, maintained at 42-48°, 18.3 g of dimethylcarbamoyl chloride was added dropwise. After stirring for an additional hour, the mass was filtered, and the filtrate was washed successively with 30-ml portions of water, dilute sodium bicarbonate solution, water, dilute hydrochloric acid, and water. The organic layer was dried over magnesium sulfate, concentrated and distilled to give 21.1 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N,N-dimethylcarbamate, b.p. 113-117° (0.20 mm Hg), n \51.5266. The structure was confirmed by nuclear magnetic resonance studies.

Analysis: Calculated for C13H17<N>O;): N 5.96. Found: N 6.10.

When using the technique described in example 1, the compound 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N,N-dimethylcarbamate showed 85 percent mortality for Mexican bean beetle, 100 percent mortality for Oncopeltus fasciatus, 100 percent mortality for pea aphids and 100 percent mortality for houseflies.

Example 7.

Preparation and properties of 2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl-N-methylthiocarbamate.

The chlorochloroformate ester intermediate was prepared according to the method of Rivier (Bull. soc. chim, (France), (3), 35, 837 (1906)) from 34.5 g of thiophosgene and 49.2 g of 2,3-dihydro- 2,2-dimethyl-7-benzofuranol in 150 ml of chloroform. 73 grams of. fine, needle-like, yellow crystals with melting point 92-93° were obtained after recrystallization from hexane. The structure of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-chlorothioformate

was confirmed by infrared analysis.

This ester was converted to the carbamate ester as follows: A cold solution of 3 g of anhydrous methylamine in 50 ml of dry hexane was added to a solution of 10 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl- chlorothioformate in 80 ml of ether to give 3.7 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylthiocarbamate, m.p. 109-110°. Another portion weighed 3.1 g and melted at 98-102°. Infrared and nuclear magnetic resonance spectra confirmed the structure.

Analysis: Calculated for C12H13N02S: C 60.74, H 6.37, N 5.90, S 13.51.

Found: C 60.66, H 6.30, N 6.12, S 12.87.

Using the test methods indicated in Example 1, the compound 2,3-dihydro-2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylthionecarbamate proved to be 100 percent lethal to Mexican bean - weevil and 100 percent fatal for Oncopeltus fasciatus.

Example 8.

Production and properties of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-ethylcarbamate.

Following the procedure described in Example 1, 16.4 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranol was reacted with 7.8 g of freshly distilled ethyl isocyanate to give 16.4 g of 2,3-dihydro-2 ,2-dimethyl-7-benzofuranyl-N-ethylcarbamate with a melting point of 103 104.5°. An analytical sample was recrystallized from methylcyclohexane to melt at 104-105°.

Analysis: Calculated for Cl3H17N03: N 5.96. Found: N 6.24.

Following the procedure described in Example 1, the compound 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-ethylcarbamate exhibited 100 percent mortality to Mexican bean beetle, Oncopeltus fasciatus and pea aphid, and 100 percent mortality to houseflies and good control of root-knot nematode at 100 ppm.

Example 9.

Preparation and properties of 2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl-N-isopropylcarbamate.

Following the procedure described in Example 1, 16.4 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranol was reacted with 9.4 g of isopropyl isocyanate and the product was recrystallized from methylcyclohexane to give 8.5 g of 2, 3-dihydro-2,2-dimethyl-7-benzo-furanyl-N-isopropylcarbamate with a melting point of 103-104°. An analytical sample was recrystallized twice from butyl ether to melt at 107.5-108.5°. The structure of this compound was confirmed by infrared analysis.

Analysis: Calculated for CHH19N03: N 5.62. Found: N 6.06.

Using the test methods described in Example 1, the compound 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-isopropylcarbamate showed 55 percent mortality for Mexican bean beetle and 100 percent mortality for Oncopeltus faciatus.

Example 10.

Preparation and properties of 4-chloro-2,3-dihydro-2,2-dimethyl-7-benzo-furanyl-N-methylcarbamate.

The chlorobenzofuranol intermediate was prepared as follows: Sulfuryl chloride (67.5 g) was added dropwise to a solution of 82.1 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranol in 250 ml of carbon tetrachloride at room temperature. (Some heating after addition of the first few drops was necessary to initiate the reaction.) The mixture was stirred at room temperature for two days until evolution of hydrogen chloride ceased. The solution was washed several times with water, dried over magnesium sulfate, and concentrated under vacuum to a purple oil. This mixture of isomers was fractionated repeatedly to give 19.2 g of 4-chloro-2,3-dihydro-2,2-dimethyl-7-benzofuranol bp 144° (10 mm Hg) and 20.5 g of 5- chloro-2,3-dihydro-2,2-dimethyl-7-benzofuranol with a boiling point of 152° (10 mm Hg). The latter compound solidified to melt at 59-60°. The position of the chlorine substituent in these samples was determined by nuclear magnetic resonance.

Analysis: Calculated for CH)HnC 1 O 2 : C 60.46, H 5.58, Cl 17.85.

Found, 4-chloro isomer: C 59.78, H 5.44, Cl 17.65. 5-Chloro-isomer: C 60.29, H 5.56, Cl 18.08.

The phenol intermediate was reacted with methylisocyanate as follows: Three drops of triethylamine were added to a mixture of 16.4 g (0.082 mol) of 4-chloro-2,3-dihydro-2,2-dimethyl-7-benzofuranol and 7.0 (0.123 mol) of methyl isocyanate in 100 ml of anhydrous ether. The mixture was refluxed for 24 hours and concentrated in vacuo to give 17.5 g of white solid, mp 140-142°. The 4-chloro-2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate was recrystallized from a benzene-hexane mixture to melt at 151.5-152.0°.

Analysis: Calculated for C12<H>14C1N03: C 56.36, H 5.51, N 5.47, Cl 13.86.

Found: C 56.91, H 5.97, N 5.67, Cl 13.82.

By following the procedure as described in example 1, the compound 4-chloro-2,3-dihydro-2,2-dimethyl-7-benzo-furanyl-N-methylcarbamate showed 100 percent mortality for the Mexican bean beetle, pea aphid, Oncopeltus fasciatus and Prodenia eridania.

Example 11.

Preparation and properties of 5-chloro-2,3-dihydro-2,2-dimethyl-7-benzo-furanyl-N-methylcarbamate.

Following the procedure described in Example 10, 17.3 g of 5-chloro-2,3-dlhydro-2,2-dimethyl-7-benzofuranol was reacted with 7.4 g (0.13 mol) of methyl isocyanate to give 19.4 g of 5-chloro-2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate with m.p. 180-182°. Recrystallization from a benzene-hexane mixture raised the melting point to 180.5-181.0°.

Analysis: Calculated for C12H14C1N03: N 5.47, Cl 13.86.

Found: N 5.47, Cl 13.76.

Following the procedures described in Example 1, the compound 5-chloro-2,3-dihydro-2,2-dimethyl-7-benzo-furanyl-N-methylcarbamate exhibited 100 percent mortality to Mexican bean beetle and Oncopeltus fasciatus.

Example 12.

Production and properties of 2, 3-dihydro-2-isopropenyl-é-benzofuranyl-N-methylcarbamate.

According to the procedure indicated in Example 1, 1.8 g of 2,3-dihydro-2-iso-propenyl-4-benzofuranol (prepared by the method of Takei and Koide, Chem. Ber. 62, 3032 (1929)) was reacted with 0.6 g of methyl isocyanate to give 2.4 g of 2,3-dihydro-2-isopropenyl-4-benzofuranyl-N-methylcarbamate with a melting point of 84-85°. Recrystallization from toluene gave 1.4 g of pure product with a melting point of 85-86°.

Analysis: Calculated for C13H15NO;): N 6.01. Found: N 6.28.

By following the test methods described in example 1, the compound 2,3-dihydro-2-isopropenyl-4-benzofuranyl-N-methylcarbamate showed 100 percent mortality for Mexican bean beetle and 100 percent mortality for Oncopeltus fasciatus.

Example 13.

Production and properties of 2, 3-dihydro-2, 2-dimethyl-7-benzo-furanyl-N-allyl carbamate.

A solution of 2.6 g of allylamine and 4.5 g of triethylamine in 25 ml of benzene was added dropwise to a solution of 10.0 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl chloroformate in 25 ml of benzene . The mixture was refluxed for two hours, cooled, filtered and the solid washed with benzene. The combined benzene solutions were extracted with water, dried over magnesium sulfate and concentrated to dryness under vacuum. The residue was recrystallized from a methanol-water mixture to give 5.7 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-allyl carbamate, m.p. 79-82°. Another recrystallization from hexane gave a sample melting at 77.2-78.0°.

Analysis: Calculated for <C>14H17NO.,: C 68.00, H 6.92, N 5.72.

Found: C 67.76, H 6.89, N 5.54.

Using the test methods described for the compound in Example 1, 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-allyl carbamate showed 100 percent mortality to Mexican bean beetle, Oncopeltus fasciatus, pea aphid and Prodenia eridania, and 100 percent mortality for houseflies.

Example 14.

Preparation of and properties for 2, 3-dihydro- 2, 2- dimethyl- 7- benzofuranyl-N- 2- propynyl carbamate.

Following the procedure set forth in Example 13, 14.0 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl chloroformate was reacted with 3.4 g of 2-propynylamine in the presence of 6.3 g of triethylamine to give 4.9 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-2-propynylcarbamate with a melting point of 97-99°, after recrystallization from a methanol-water mixture. Another recrystallization from hexane gave a sample with a melting point of 95.6-97.0°.

Analysis: Calculated for C14Hir)NO3: C 68.55, H 6.16 N 5.71.

Found: C 68.35, H 6.37, N 5.86.

Using the test methods set forth in Example 1, the compound 2,3-dlhydro-2,2-dimethyl-7-benzofuranyl-N-2-propynylcarbamate exhibited 100 percent mortality to Mexican bean beetle, Oncopeltus fasciatus, pea aphid and Prodenia eridania, and 100 percent .mortality for houseflies.

Example 15.

Production of and properties for a

mixture of 2,3-dihydro-2,2,4-trimethyl-7-ienzofuranyl-N-methylcarbamate and 2,3-dihydro-2,2,5-trimethyl-7-benzo-furanyl-N-methylcarbamate.

To a stirred solution of 232.3 g of 4-methylpyrocatechol in 700 ml of methanol at 55-60°, under a nitrogen atmosphere, 101.0 g of sodium methoxide was added. After refluxing for 1 hour, 169.3 g of 3-chloro-2-methylpropene was added dropwise, and stirring and heating were continued for another 20 hours. The solvent was removed under reduced pressure, the residue was diluted with 700 ml of chloroform, filtered and the sodium chloride was washed twice with 100 ml portions of chloroform. The combined filtrate was washed with three 100 ml portions of water, dried over magnesium sulfate, concentrated and distilled to give 204.0 g of a dark red oil. Distillation of this oil gave 83.5 g of a fraction boiling at 70-74° (0.03 mm Hg), after the first low-boiling fraction had been removed. The fraction, n \,fi 1.528, was a mixture of 2-((methylallyl)oxy)-p-cresol and 6-((2-methylallyl)oxy)-m-cresol. These isomers could not be separated by redistillation or by gas chromatography.

Rearrangement and ring narrowing were carried out by heating 152 g of a mixture of 2-((2-methylallyl)oxy)-p-cresol and 6-((2-methylallyl)oxy)-m-cresol in an oil bath. An exothermic reaction took place at 185°, and the temperature rose to 220°. The mixture was held at 205-210° for four hours, was cooled and distilled to give 57.1 g of a mixture of 2,3-dihydro-2,2,4-trimethyl-7-benzofuranol and 2,3-dihydro -2,2,5-trimethyl-7-benzofuranol, m.p. 128-130° (8 mm Hg), n 2D5 1.535. The presence and structure of these isomers were confirmed by nuclear magnetic resonance studies. The mixture could not be separated by redistillation or by gas chromatography. Analysis: Calculated for C2H14O2: C 74.13, H 7.92. Found: C 74.23, H 7.98.

The mixture of benzofuranols was esterified according to the method described in example 1. 38 grams of a mixture of 2,3-dihydro-2,2,4-trimethyl-7-benzofuranol and 2,3-dihydro-2,2,5- trimethyl-7-benzofuranol was reacted with 19.4 g of methyl isocyanate to give 20.5 g of a white, crystalline solid with a melting point in the range 110-130°. This mixture of 2,3-dihydro-2,2,4-trimethyl-7-benzofuranyl-N-methylcarbamate and 2,3-dihydro-2,2,5-trimethyl-7-benzofuranyl-N-methylcarbamate was not separated.

Following the evaluation methods described in Example 1, this mixture of isomers exhibited 100 percent mortality to Mexican bean beetle, pea aphid Oncopeltus fasciatus and Prodenia eridania.

Example 16.

Systemic activity.

These compounds exhibit useful systemic activity. This can be illustrated as follows: A 1% solution of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate in acetone was diluted with water to a concentration of 156 ppm of the active ingredient. The roots of pinto bean plants at the two-leaf weight stage were cut off, and the plant stems were immersed in the solution of the test compound. After three days of immersion of the plant stems, the plant leaves were infected with the experimental insects. Three days after inflation, the percentage mortality was counted. This compound caused 100 percent mortality of Mexican bean beetle, pea aphid, two-spotted mite and Prodenia eridania.

A 1% solution of 2,3-dihydro-2,2-dimethyl-4-benzofuranyl-N-methyl-methylcarbamate in acetone, diluted with water to a concentration of 78 ppm of the active ingredient, effected by a corresponding test 100 percent mortality of Mexican bean beetle, pea aphid and two-spotted mite.

The above results show the excellent systemic activity.

The active compounds can be mixed with common additives and emollients when preparing preparations. They can be incorporated into any of the excipients and carriers that are normally used to facilitate the spread of active ingredients, taking into account the fact that the formulation and method of use of the poison can affect the activity of the material. These compounds can e.g. used as spray liquids, powders, grains or ætter, in the area where pest control is desired, as the choice of method of application obviously varies with the type of pest and the environment. These compounds can thus be formulated as grains with a large particle size, as powdery dusts, as wettable powders, as emulsifiable concentrates, as solutions and the like.

Dusts are mixtures of the active ingredients with finely divided solids such as talc, attapulgite clay, diatomaceous earth, pyrophyllite, chalk, calcium phosphates, calcium and magnesium carbonates, sulphur, lime, flour and other organic and inorganic solids that act as dispersants and carriers for the poison. These finely divided solids have an average particle size of less than approx. 50 microns. A typical dust preparation that is particularly suitable contains 10 parts poison, 30 parts bentonite clay and 6 parts talc.

The compounds can be made into liquid concentrates by dissolving or emulsifying in suitable liquids, and into solids

concentrates by mixing with

talc, clays and other known solid carriers used for pesticides. The concentrates are preparations containing approx. 5-50 per cent poison and the rest inert material comprising dispersants, emulsifiers and wetting agents. The concentrates are diluted for practical use with water or another liquid for aqueous spray liquids or with an additional solid carrier for use as a dust. Typical carriers for solid concentrates (also called wettable powders) include Fuller's earth, kaolin clays, silicic acid and other highly absorbent, easily wettable inorganic diluents. A suitable solid concentrate contains 25 parts poison, 72 parts bentonite clay and 1.5 parts each of sodium lignosulphonate and sodium lauryl sulphonate as wetting agents.

Suitable liquid concentrates include the emulsifiable concentrates, which are homogeneous, liquid or paste-like preparations that are easily dispersed in water or other dispersing agent, and which may consist entirely of the poison with a liquid or solid emulsifying agent, or which may also contain a liquid carrier, such as xylene, heavy aromatic benzines, isophorone and other non-volatile organic solvents. For use, these concentrates are dispersed in water or another liquid carrier, and are normally applied by spraying to the area to be treated.

The concentration of the poison in the dilution that is usually used to control insects and other pests is normally in the range of approx. 2 to approx. 0.001 percent Many variations of spray and dust preparations in the art can be used by introducing the compounds in preparations known or obvious in the art.

Typical wetting, dispersing or disintegrating agents used in these preparations include e.g. the alkyl and alkyl-aryl sulfonates and sulfates and their sodium salts, alkyl amide sulfonates, including 5-methyl taurides; alkylarylpolyetheral alcohols; sulfated higher alcohols, polyvinyl alcohols; polyethylene oxides; sulfonated animal and vegetable oils; sulphonated petroleum oils; fatty acid esters of polyhydric alcohols and the ethylene oxide addition products of such esters; and the addition products of long-chain mercaptans and ethylene oxide. Many other types of suitable surfactants are commercially available. The surfactant, when used, usually comprises

from 1 to 15 percent by weight of the preparation.

Other suitable preparations include

simple solutions of the active ingredient in a dispersant in which it is

completely soluble in the desired concentration, such as acetone or other organic solvents. Granular preparations, in which the poison is carried on relatively

coarse particles, are of particular use for

spread from the air and to cover crops again (cover crop

canopy”). Spray liquids under pressure, typically aerosols in which the active ingredient is dispersed in finely divided form as a result of evaporation of a low-boiling, dispersing, dissolving carrier such as freon, can also be used. Åter is usually prepared by mixing liquid or solid concentrates with suitable food, such as a mixture of cornmeal and sugar.

The preparations can be mixed and used with other active ingredients, including other insecticides, fungicides, nematocides, plant growth regulators, fertilizers, etc. When using the chemicals, it is obvious that an effective amount and concentration of poison must be used.

Claims (5)

1. Pest control agent, characterized in that it contains as active ingredient one or more dihydro-7-benzofuranyl and dihydro-4-benzofuranyl carbamates of the formulas: where R], R 2 , R 3 and R 4 are each hydrogen atoms, alkyl or alkenyl groups of one to three carbon atoms; R 5 and R 6 are each hydrogen atoms, alkyl, alkenyl or alkynyl groups of one to three carbon atoms; Y means one or more substituents selected from hydrogen atoms, halogen atoms and lower alkyl groups, n is an integer from 1 to 3; and X is oxygen or sulfur. 2. Agent as stated in claim 1, characterized in that it contains 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate as active ingredient. 3. Agent as stated in claim 1, characterized in that it contains 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-ethylcarbamate as active ingredient. 4. Agent as stated in claim 1, characterized in that it contains 4-chloro-2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate as active ingredient. 5. Agent as stated in claim 1, characterized in that it contains 2,3-dihydro-2,2,4-trimethyl-7-benzofuranyl-N-methylcarbamate as active ingredient.